1. Field of the Invention
The present invention relates generally to a key-data inputting in a mobile communication terminal, such as mobile phones, for use in digital mobile communication systems. The present invention relates more particularly to a single keyed data inputting device adapted for entering desired key-data, for example, by pushing, drawing or depressing a single key with respect to a body of the mobile phone, and also to the mobile communication terminal provided with the single keyed data inputting device.
2. Description of the Related Arts
Conventionally, mobile communication terminals such as mobile telephones may be classified into a bar-type terminal, a flip-type terminal or a folder-type terminal in accordance with to their appearance and body structure, or further into a wrist-type terminal or a neck-wearable terminal in accordance with the wearing style with their users. Furthermore, they may be classified into a voice-communication dedicated terminal, an image-communication serviceable terminal or an Internet protocol based terminal according to their functions when using them. Most recently, the flip-type or folder-type mobile terminals have become popular among mobile subscribers or users more than the bar-type one, but in the near future, it is most likely that the various types of wearable mobile phones such as a wrist-type terminal or a neck-wearable terminal will be favored among younger users because they may be more convenient and may not need to be hand held during use as compared to those conventional ones.
Further describing the folder-type terminal by way of an example of the prior art mobile phone, it is usually comprised of a main body, a folder and a hinge means coupling the main body and the folder, the hinge means being adapted to pivotably open and close the folder to a predetermined angle position upon using of it. The main body further includes a data input means and a microphone, while the folder includes a data output means and a speaker. The data input means of a known mobile phone is provided with a keypad having a set of keys or buttons arranged in a multiplicity of rows and columns, for example, 3×4 matrix, while the data output means normally includes an LCD (liquid crystal display) module or a display panel. Alternatively, a touch screen or any voice recognition means may be utilized as the data input means to enter any desired key data.
Among the various data input means, heretofore described, for use in mobile phones, a data inputting system using a keypad has been most prevailing in the state of the art owing to the simplicity of construction, because its user is able to conveniently input any desired data on his or her mobile phone by means of merely depressing one or more keys with fingers sequentially. This keypad assembly normally uses a sort of direct key entry system, in which activation of any one of desired key data or functions can be effected by depressing a corresponding key or button by one of user's fingers as occasion demands.
One known keypad generally consists of a set of data keys for inputting numerals or characters (for instance, the alphabet) into the phone, and a set of function keys for operating starting and termination of a call, or selecting a menu where appropriate. Thus, it is preferably designed to have more than 15 keys in one keypad, most preferably 15 to 20 keys in total. Recently however, it has been often demanded for some user's mobile phones to be provided with more than 20 keys, in particular in case where the user prefers to use his or her mobile phone for the purpose of enjoying Internet communications service, e-mail transmission, phone-chatting, short-message-service (SMS), etc. In the nearest future, it is most likely that a keypad consisting of more than 20 keys, even more up to 30 keys, would be preferred by some mobile phone subscribers.
A recent trend in developing mobile phones has been to build lighter and smaller body for satisfying the users' increasing needs. Such a mobile phone with lighter and smaller body essentially requires smaller sized LCD display panel and keypad. These small LCD displays and keypads will most likely create some disadvantages for the users. For example, it will not be easy for a user to read out displayed data because the size of images on it becomes smaller and it will not be convenient for the user to enter data onto a small-sized keypad with fingers. Accordingly, overcoming such disadvantages has been considered as one of the most significant factors in development of more compact and smaller sized mobile phones in this field of art. Furthermore, the keypad assembly utilized for a data input means in the known and conventional mobile phones generally has the following disadvantages:                Firstly, those conventional keypads normally require the keypad arrangement consisting of more than at least 15 keys on it, thereby causing a problem to development of smaller sized and more compact mobile phone, since each key of the keypad must be depressable by a user. Such a key depressing action by fingers onto a keypad will eventually cause a considerable degree of technical limitation to design of smaller sized keys, thereby causing a similar problem to design of smaller and more compact sized keypad assembly to satisfaction of increasing needs from the users; and        Secondly, in order to input a desired key data, a user has to depress a corresponding key by fingers. These keys are invariably much smaller than the user's fingers and thus may be quite annoying to some users when using them. This troublesome key depressing action would also cause entering incorrect data. In particular, in case of repeating a series of key depressions on the keypad, it will sometimes cause a key error depressing an undesired key owing to incorrect manipulation of fingers, which mostly results from complicated key-depressing system in keypads of the conventional mobile phones.        
Finally, the conventional keypad assembly creates a considerable degree of technical limitation on the design of an external appearance of the mobile phone. For example, designers of these mobile phones are burdened with having to design an outer body incorporating a conventional keypad assembly.